The preceptual experience of young infants depends both on how they are able to act on their world and the properties of that world. One focus of this proposal is to describe the changes in infants' abilities to act visually on their world in the first two months of life. Infant visual scanning activity is assumed to reflect infant visual abilities. Historically, the visual world has been divided into such properties as form and depth but young infants may respond on the basis of the whole object and not to form and depth separately. Thus, infant visual responses may be a function of the developing visual capabilities in interaction with particular form/depth combinations. Several investigators have shown that two-month-old infants respond differentially to planometric and stereometric stimuli but the data are inconsistent about whether infants younger than two-months respond to depth. This inconsistency may be due to the type of form/depth combinations presented to the infants. Study I is designed to test developing infant visual scanning activity of newborn, one-month, and two-month-old infants to stimuli varying both in form and in depth. One possible explanation for infants' differential response to form/depth combinations is a developing sensitivity to disparity cues. Study II is designed to test this hypothesis by varying infant's opportunities to use binocular vision.